A gear shaper machining using a pinion cutter described in JP2012-115940A and a skiving using skiving cutters described in JP2015-058505A and JP2014-155990A are known as a gear machining method using a gear cutting tool. The gear cutting tool such as the pinion cutter and the skiving cutter is provided with cutting blades which are able to cut out a gear (workpiece).
A gear cutting tool having a discharge port on a center side thereof is described in JP2015-164751A. The gear cutting tool is configured to discharge a coolant liquid from the discharge port positioned on the center side of the gear cutting tool toward blades positioned on an outer peripheral side thereof. Consequently, chips generating during machining of the gear may be removed from a cutting portion by the coolant liquid discharged therefrom.
A gear cutting tool provided with filling ports formed in rake faces of a plurality of blades on the outer peripheral side thereof is described in JP51-65481A. A coolant liquid is supplied from the filling ports. In addition, a grind stone structure having a channel configured to supply a coolant liquid into an interior of a grind stone is described in JP-UM-A-63-763.
Here, the gear machining repeats intermittent machining, and thus the gear cutting tool reaches the end of its life earlier due to wear, chipping and the like of blades of the gear cutting tool. Accordingly, in JP2013-169621A and in JP2000-280119A, various ideas for elongation of a service life of the gear cutting tool are devised.